Fork spring question

Hey Gents,

as some of you might remember, my fork seal went out on the right side & I figured while I was in there I might as well swap out the springs. well........ this has turned into some frustration with the vendor (not quite resolved yet).

anywho, I was reading the instructions & they want you assemble this & measure that & subtract this & add that. it seemed like a bunch of sillyness to me
A. considering that the preload is adjustable
B. I have all the parts out of the old one, why not just use it as a base to figure out how long the new spacers need to me.

So.......

what seemed logical to me was that the old spring was 380 mm long, the old spacer was 50 mm long together they are 430 mm. the new spring is 340 mm long, so by my elementary math, the new spacer should be 90 mm long. simple right??? this is assuming that I was using all the same spacers & washers & whatnot from the original springs.

well, I figured I would follow the directions that came with the springs (which were quite dissorganized) & the calculations for the spacer length came out to be 90 mm long.



Does anyone see any fault with my logic??

Bob

 

BTW, this is a cardridge style fork with an external top out spring.

Bob

 

That's how I would do it, too. I should add that my only experience with suspension mods is my SV650, which has the damper-rod style forks. But unless I am missing something: spring length, preloading and sag aren't affected by the damping mechanisms.

In short, I agree. The worst thing that can happen is that your preload adjusters won't give you the proper sag within their adjustment range, and you'll have to make new spacers.

 

thanks, I will give it a go & see what happens.

Bob

 

Sounds good to me, it's how I'd start the dial in anyway. You don't have to say who the vendor is but I share your frustration with the 'shim shufflers'. You mention that you want a street set up and weigh 130 lbs, their eyes glaze over and you get the rote "you need stiffer springs, 'gold valves', platinum shims, this and that drilled" etc. Good luck with your set-up.

 

Umm, Race Tech? I got the same advice replacing the stock progressive springs in my '99 with their .95 straight rate springs. Cut spacers to match the original spring/spacer length. Front end was pointed at the sky after that.

Start with that approach and try to set your sag, but realize you may need to pull the spacer back out and cut them further. I ended up going in twice and taking another 25mm off total. Fortunately that's an easy job. Good luck.

 

Well, I don't measure parts - I measure the preload. Here is the procedure I use:

1) First determine the amount of preload you want on the springs. This will come from RaceTech or your suspension tuner. Normally it's something like 15mm.
2) Install everything in the forks but do not thread on the fork cap to the stanchion tube.
3) Raise the stanchion tube up until it stops. Measure from the top of the tube to the step on the cap where it seats.
4) Take this measurement and compare it to the desired. Cut/add as necessary. It's a 1:1, if it's 4mm too much then cut 4mm off the spacer. If it's not enough you need to cut a longer spacer.


I don't measure the length of the actual spacer because there are tolerances and such that it has to take up. The length of the spacer doesn't really matter, it's the actual preload. I hope this helps!

 

Shoot............. 4 steps. why couldn't the instructions be that simple??? LOL.

thanks again
Bob